Chimeric Antigen Receptor Modified T Cells Targeting BCMA for the Treatment of Relapsed/Refractory Multiple Myeloma

Inclusion Criteria: 1. Age 18-80 years, no gender restrictions; 2. Diagnosed with refractory/relapsed multiple myeloma through physical examination, pathological examination, laboratory tests, and imaging studies; 3. Flow cytometry or histology confirms positive BCMA expression in myeloma cells; 4. As judged by the investigator, the expected survival time is \>3 months; 5. ECOG performance status score ≤2, KPS \>60%; 6. The patient has good liver, kidney, heart, and lung function: ALT and AST ≤2.5×ULN, those with liver involvement can be relaxed to ≤5×ULN; serum total bilirubin \<34 μmol/L; creatinine clearance rate \>30 mL/min; heart ejection fraction (EF) ≥40%, no pericardial effusion and significant arrhythmia; indoor SpO2 ≥92%; 7. Peripheral blood lymphocyte absolute count ALC ≥0.5 ×10\^9/L, PLT \>30×10\^9/L, Hb \>80 g/L and has a single collection venous access, and there are no other contraindications for hematopoietic cell separation; 8. Those with fertility must agree to use highly effective contraceptive methods; 9. The subject or their legal guardian can understand and is willing to sign a written informed consent form voluntarily. Exclusion Criteria: 1. Pregnant or nursing women, as well as women planning to become pregnant within the next six months; 2. Positive virology tests for hepatitis B, hepatitis C, HIV, syphilis, or cytomegalovirus; 3. History of other tumors (except for those with skin or cervical in situ cancers that have been cured by radical treatment and show no evidence of disease activity); 4. Previously received treatment targeting BCMA; 5. Underwent autologous hematopoietic stem cell transplantation within the last 6 weeks; 6. Presence of uncontrolled active bacterial or fungal infection; 7. Allergic to research-related drugs or cell components; 8. Presence of active autoimmune diseases; 9. Currently have unstable or active ulcers or gastrointestinal bleeding; 10. Unable to cooperate with treatment and efficacy evaluation due to mental or psychological disorders; 11. Received other experimental drug treatments within the last 3 months; 12. The researcher believes that for other reasons, the individual is not suitable for the clinical trial.